4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

Fuel issues... any ideas?!

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Old Aug 26, 2015 | 08:19 AM
  #1  
timeformiller44's Avatar
timeformiller44
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From: New York
Default Fuel issues... any ideas?!

Finally put the car on the road after a long time.

have ported and polished heads, with full exhaust, JLT CAI, SCT livewire. not to much

Was getting lean codes. bank 1 and 2, checked fuel pressure, was ####, so replaced the pump with a Ford GT 255lph pump. wired it in and such, now at Higher RPMS, i lose fuel, big time, like 10psi at 5300rpm, also corraltes with the voltage higher voltages, less fuel pressure, i have it datalogged if anyone wants to see it, i can send the file, i am clueless, i know there are no kinked lines anywhere, checked multiple times, newer filter. and i doubt its in the tune for something so drastic of a drop in pressure.

either new pump is failing, or i have the wiring backwards and the polarity is killing pressure when seeing voltage spike.

but my car should be running fast than a 9 in the 1/8 because it has before, now i am running 10's and slower.......
Old Aug 26, 2015 | 08:53 AM
  #2  
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school boy
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From: kentucky
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It sounds fuel pump related. Might try and replace it. If the wires were reversed, you would have no pressure.
Old Aug 26, 2015 | 09:09 AM
  #3  
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timeformiller44
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damn pump wasnt cheap and its newer.. UGH
Old Aug 26, 2015 | 11:25 AM
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school boy
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Might try and see if youre receiving full voltage at the pump somehow while driving.
Old Aug 26, 2015 | 12:03 PM
  #5  
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Phillip123
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Maybe its a bad coil.
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